ServiceDesk across two domains

All,

Here is the scenario:  Two Domains (A & B)

Domain A is where all of the Symantec Products are managed and housed (ServiceDesk, SMP, & such)

Domain B is Secure and only has a one way connection back to A, again Domain B can send info to A, but A cannot send info to B

How do the users in Domain B use ServiceDesk in Domain A?

Create Local accounts that they can use?

Create a tempate in their SharePoint that will send an email to ServiceDesk and generate an auto ticket?

To use there AD accounts how would they authenticate back to Domain B?

Thanks a bunch for any insite.